Novel nutritional function of sphingolipids via secreted exosomes

本研究通过分析鞘磷脂(SPM)处理的肝癌细胞或经SPM处理的大鼠血清制备的外切体的组成，提出了鞘磷脂可能的新的营养功能。人肝癌细胞经SPM处理后，细胞增殖能力下降。经SPM处理的肝癌细胞条件培养液对肝癌细胞具有抗增殖作用。SPM处理引起分泌型外切体miRNA组成的改变，从而抑制了周围细胞的增殖。从SPM插管的大鼠血清中制备的外切体显著促进培养的肌细胞对葡萄糖的摄取。这一结果表明，口服SPM可能会影响血清外切体的组成，并在活体内表现出一定的生理效应。这些结果清楚地表明，鞘脂可能会影响从细胞分泌或进入血清的外切体的组成，从而提示鞘磷脂具有新的营养功能。

The possible new nutritional functions of sphingolipids are proposed in this study, by analyzing the composition of exosomes prepared from sphingomyelin (SPM)-treated hepatoma cells or SPM-intubated rat sera. The treatment with SPM of human hepatoma cells resulted in the decrease of proliferation. The conditioned media of SPM-treated hepatoma showed an anti-proliferative effect on hepatoma cells. SPM treatment caused the change in miRNA composition of secreted exosome, thus suppressed the proliferation of surrounding cells. The exosomes prepared from SPM-intubated rat sera significantly promoted the glucose uptake of cultured muscle cells. This result suggests the possibility that orally-intubated SPM affects the composition of serum exosomes and shows some physiological effects in vivo.These results clearly show the possibility that sphingolipids can affect the composition of exosomes secreted from cells or into sera, thus suggesting novel nutritional functions of sphingolipids.